Counting is used to find the number of elements in a group or a set. After learning how to count children are taught how to add. The process of addition which uses the plus sign + gives you a sum or a total and this is a method of counting. Math is about seeing patterns and then following some basic rules. Numbers have many specific rules about how they can interact with other numbers. There are rules that explain how to “add” or “multiply” two “numbers” together and these operations have special relations which they need to follow, such as satisfying commutative, associative, and distributive laws. If a large enough list of rules is developed, (in math this is termed axioms), many other facts about numbers can be deduced. Adding 2n plus 2n should not be foreign to you.